1. Field of the Invention
The present invention relates to a contact pressure system that can be used especially in continuously variable transmissions, in a continuously variable transmission with a contact pressure system, as well as a method for operating such contact pressure systems and/or continuously variable transmissions.
2. Description of the Related Art
Continuously variable transmissions, as well as contact pressure systems for such continuously variable transmissions and methods for the operation of such continuously variable transmissions and contact pressure systems, are known. In a known continuously variable transmission that can be used especially as a motor vehicle transmission, there are provided two pairs of conical disks whose conical disks are arranged so that they can be moved relative to each other. An endless torque-transmitting means is placed around the pairs of conical disks. The transmission ratio between those pairs of conical disks is achieved by means of coordinated adjustment of the particular pairs of conical disks, specifically, in such a way that the spacing between the conical disks of the first pair of conical disks is enlarged when the spacing between the conical disks of the second pair of conical disks is reduced, and conversely. To retain a transmission ratio that has been set, a contact pressure system with a torque sensor is utilized, which essentially is loaded by a moment that, in terms of magnitude, also exists at the input side set of conical disks. The torque acting on the torque sensor is converted, via a ramp arrangement, into a linear force, which acts upon the set of conical disks. The transmission ratio is essentially retained in cooperation with a force that acts on the set of conical disks from the endless torque-transmitting means.
The object of the invention is to produce a differently designed contact pressure system, a differently designed continuously variable transmission, as well as a differently designed method for the operation of a contact pressure system or a continuously variable transmission.
In accordance with a particular aspect, the object of the invention is to produce a contact pressure system for continuously variable transmissions wherein the contact pressure force can be adjusted in accordance with or in approximation to the current requirement with a high degree of operational reliability.
In accordance with a particular aspect, the object of the invention is to produce a differently designed contact pressure system, a differently designed continuously variable transmission, as well as a differently designed method for the operation of a contact pressure system or a continuously variable transmission, by which under different load directions, as well as load direction changes, a high degree of operational reliability is achieved.
The problem is solved by a contact pressure system which has at least one feature of the features that are described in the following description or that are shown in the drawings.
The problem is further solved by a continuously variable transmission which has at least one feature of the features that are described in the following description or that are shown in the drawings.
The problem is further solved by a method for operating a continuously variable transmission and/or a contact pressure system, that has at least one feature of the features described in the following description or that are shown in the drawings.
The invention is particularly solved by a contact pressure system that has a torque sensor system, that, on the input side, can be loaded with a torque, and that, on the output side, produces a contact pressure force which depends on the torque that is applied on the input side. This contact pressure system further has a transfer unit that transfers that torque or that power. By a transfer unit in the sense of the present invention, what is especially to be understood is a unit that is arranged within a power or moment transfer section and that causes the output moment or the output power of that unit to be changed relative to the input moment or the input power.
In particular, in the sense of the present invention, the transfer unit is to be understood to be a transmission. The transfer unit is preferably formed mechanically. Thereby it is not intended to restrict the invention in any way. The transfer unit can also be hydraulic, or hydraulic and mechanical, or formed in other ways.
It is especially preferred in accordance with the present invention that the contact pressure system operates so that in a motor vehicle with an internal combustion engine and a continuously variable transmission, power or a moment introduced from the internal combustion engine into the contact pressure system is increased within the contact pressure system, and the output side of the contact pressure system loads the continuously variable transmission.
In accordance with the invention, there is provided, especially, a contact pressure system for a continuously variable transmission, which system is associated with at least one set of disks of the continuously variable transmission. Thereby it is provided that the contact pressure system has a torque sensor system or a torque sensor, and that the torque that is introduced on the input side into the torque sensor is different from the torque that is transmitted between the sets of disks, in particular by an endless torque-transmitting means.
It should be noted that, in the sense of the present invention, by input side is to be understood preferably the side of the contact pressure system or of the torque sensor that, in the flow of power or the flow of torque, faces an internal combustion engine when a contact pressure system in accordance with the invention is utilized in a motor vehicle with an internal combustion engine in order to generate a contact pressure force on a continuously variable transmission of that motor vehicle.
It should further be noted that by a contact pressure system in the sense of the present invention is to be understood a system that is loaded with a torque on the input side and that on the output side produces a force that is especially preferred to be linearly directed. The invention should not be restricted to such contact pressure systems. The contact pressure system in accordance with the invention can especially be designed as a dry operating or a wet operating contact pressure system.
In accordance with the invention, there is particularly provided a contact pressure system with at least one torque sensor system, whereby the contact pressure system or the torque sensor system has ramps that extend at an angle with respect to the circumferential direction of the contact pressure system or the torque sensor system, and that at least cooperate in bringing about a situation where the contact pressure force produced by the contact pressure system is dependent upon the torque. The torque dependence applies especially to a torque with which the contact pressure system or the torque sensor is loaded. For different torque directions or rotation directions different ramps are preferably provided. Further, preferably different freewheels are provided for the different rotation directions. The different freewheels are in that case coupled together in such a way to ensure that both freewheels will not simultaneously block a rotational movement, and thereby through the cooperative action of the freewheels movability in both directions of rotation is simultaneously blocked.
It should be noted that by the term xe2x80x9cat an angle to the circumferential directionxe2x80x9d in the sense of the present invention, it is especially to be understood that the angle is given within a circumferentially defined curved surface and/or by an angle to such a fictitious curved surface.
In accordance with the invention, there is particularly provided a contact pressure system with at least one torque sensor system, whereby the contact pressure system or the torque sensor system has at least one double freewheel system that cooperates with the torque sensor.
By a double freewheel or a double freewheel system, in the sense of the present invention, is especially intended a freewheel system that has different freewheels that are so coupled together that, as a function of at least one position of the first of the freewheels, the position or the position range of the other of the freewheels can essentially be determined unambiguously. That position range includes only a part of all possible positions of the other freewheel. In particular, in accordance with the invention a double freewheel system is to be understood to be a system with two freewheels that are coupled together in such a way that a position is established in which both are defined to be open. Preferably, the freewheels are provided for different rotation directions so that the first freewheel can transmit a torque in a first direction of rotation, and that the second freewheel can transmit a torque in a second direction of rotation opposite to the first one. The freewheels are preferably coupled with a ramp system of a torque sensor system.
In accordance with the invention, there is provided, in particular, a contact pressure system with a torque sensor system that, on the output side, can produce a contact pressure force that, for example, is provided to load a set of disks of a continuously variable transmission, where the contact pressure force is dependent upon a torque that is applied on the input side of the contact pressure system or the torque sensor system, as well as on the direction of rotation of that torque. Further there is provided a switchover device that, when the direction of rotation is changed, switches over between predetermined control characteristics that depend on the direction of rotation.
A torque sensor system or a torque sensor in the sense of the present invention is particularly formed so that it has, respectively, two different ramps or ramp arrangements, of which one is intended for deceleration and one for acceleration. An arrangement of several ramps is especially designed in such a way that the ramps have a substantially identical contour.
In a motor vehicle with a contact pressure system in accordance with the present invention assembled with a continuously variable transmission, acceleration is particularly provided when an internal combustion engine that is arranged on the input side of the continuously variable transmission loads it or supplies it with energy, so that it causes to make available energy or torque at the output side of the continuously variable transmission that can drive a motor vehicle. Deceleration is particularly provided in a motor vehicle with a contact pressure system in accordance with the present invention, as well as a continuously variable transmission, when a torque is introduced into the continuously variable transmission at the output side of the continuously variable transmission, and which is conducted in the direction of the internal combustion engine through the continuously variable transmission in the drive train. Acceleration is particularly provided in a motor vehicle when a fuel proportioning member, such as a gas pedal, is operated, and deceleration is provided when the fuel proportioning member is not operated during movement of the motor vehicle.
The rotation-direction-dependent control characteristics preferably control the contact pressure force and are at least partly determined, in a particularly preferred manner, by the design or the geometry of the ramps, and thus particularly at least determine the acceleration ramp or the deceleration ramp.
In accordance with the invention there is provided, in particular, a contact pressure system with a torque sensor system as well as with a device that guarantees that at least one of the respective ramps or the respective ramps of the torque sensor, thus, particularly, the acceleration ramps and the deceleration ramps, lie in a power transmitting direction with each of the adjoining power transmitting components. The apparatus further guarantees that as a function of the load direction of the contact pressure system or the torque sensor system, one of the respective load-direction-determined ramps will be arranged in the power flow path. In particular, there is provided in accordance with the invention one or several deceleration ramps that are connected in the power flow path when a continuously variable transmission or a motor vehicle is operated in deceleration, and that one or several acceleration ramps are connected in the power flow path when the continuously variable transmission for the motor vehicle is operated during acceleration. In accordance with the invention, it is especially provided that the apparatus guarantees that a transmitting body will in each case lie in contact with one of the ramps adjoining the transmitting body.
A transmitting body in the sense of the present invention is particularly an element that is provided in a moment sensor, and between two relatively movable parts, such as ramps of a ramp arrangement, arranged in such a way that a torque can be transmitted between those parts by the transmitting body. The transmitting body is particularly arranged between two ramps that are in each case arranged in the same direction of rotation. It is certainly also preferred that the transmitting body be arranged between a ramp and a surface not shaped as a ramp.
A transmitting body in the sense of the present invention is particularly formed as a roll or roller, or as a ball, or in other ways. Particularly preferred in the sense of the present invention is a transmitting body that is formed in such a way that its surface contour makes possible rolling or sliding of the transmitting body on another body.
The apparatus particularly guarantees that the transmitting body constantly lies against one of the surfaces of the torque sensor system, which are arranged to be movable with respect to each other, and between which the transmitting body transmits or can transmit torque when the corresponding direction of rotation is provided in which the torque is to be transmitted by that transmitting body.
In accordance with the invention there is particularly provided a contact pressure system with a torque sensor system wherein the torque sensor system has differing ramps. The torque sensor system particularly has at least a first ramp by which a torque is transmitted when the torque sensor system is loaded in a first direction of rotation, as well as at least a second ramp, by which a torque is transmitted or is to be transmitted, when the torque sensor system is loaded in a second direction of rotation opposite to the first one. The first ramp is particularly a deceleration ramp and the second ramp is particularly an acceleration ramp, or conversely. In accordance with the invention there is further provided a freewheel unit that has at least one first freewheel associated with the first direction of rotation, as well as a second freewheel associated with the second direction of rotation. In accordance with the invention, it is guaranteed that jamming of the free wheels by a reversal of the torque sensor is prevented.
By a reversal of the torque sensor in the sense of the present invention is to be understood that in a rapid change of load direction, the moment sensor will return to a null position from a ramp or flank, such as the acceleration flank or the deceleration flank, and subsequently is moved to the other of those flanks or ramps to the currently needed position. In doing so, angular play  greater than 180xc2x0 can occur that can lead to impacts in the drive train, and in that case possibly a resulting loss of comfort or damage to components. Those and also other negative influences are certainly particularly avoided by the invention. In particular, it is further guaranteed in accordance with the present invention that the freewheels in such a reversal will not be jammed against each other.
In accordance with the invention, there is particularly provided a contact pressure system with a torque sensor system that has a spring system, whereby the spring system operates cooperatively with the torque sensor system. Preferably, the torque is introduced into the torque sensor system on the input side through the spring system or through a part of the spring system. Especially preferred is a provision that the torque sensor system is coupled only through the spring system, or a part of the spring system, with the input side, that is, particularly the side or with components that are arranged on the side, which in a motor vehicle with a contact pressure system installed on a continuously variable transmission of the motor vehicle is turned toward, or which faces away from the continuously variable transmission, so that torques between input side components and the torque sensor system in the direction of the output side are transmitted only by the spring system or a part of the spring system.
In accordance with a preferred embodiment of the invention, the transmission ratio of the transmission unit is adjustable. It is particularly preferred that the transmission ratio apparatus is formed as a gear unit and, to be sure, especially as a planetary transmission, whereby the transmission ratio of the transmission of that type is set so that of the components carrier, sun gear, and ring gear, a structural component is coupled on the drive side, in particular in the direction of the internal combustion engine, a further component is coupled with the torque sensor system, and the third of those components is loaded by an adjusting or control device or in some other way, which operates to control the transmission ratio between both of the other components. Particularly preferred is provided that the sun gear is loaded by an internal combustion engine of a motor vehicle, the carrier of the planetary transmission loads a torque sensor, and the ring gear is loaded by a control or adjustment mechanism or in other ways. If necessary, the planet gear is arranged to be non-rotatable.
The transmission ratio of the transmission unit or of the gear unit is constant or not constant.
Preferably, the differential moment between the carrier moment and the input moment, or the moment of the sun gear, is returned as a reactive moment into the planetary transmission by the moment sensor output, or the output side of the moment sensor and the ring gear of the planetary transmission. In accordance with a preferred embodiment of the invention, the planet set of a planetary transmission is not impacted by the power train output but rather by the power train moment.
The transmission unit, which, in particular, is made as a gear unit, and which in a particularly preferred manner is formed mechanically, is, in accordance with a preferred embodiment of the invention, arranged on the input side of the torque sensor, thus, in a contact pressure system installed in a motor vehicle, in particular, between the torque sensor and the internal combustion engine of the motor vehicle. Preferably, the transmission unit or the gear unit is provided on the output side of the torque sensor system, or a gear unit is provided both on the input side and the output side of the torque sensor system.
In accordance with a preferred embodiment of the invention, the transmission unit is a so-called round or non-round gear arrangement. Particularly preferred, all torques that are introduced into the transmission unit or that derived from the transmission unit are torques with respect to the same or, from time to time, a concentric axis of rotation.
When a planetary transmission is used in the sense of the invention, the planets in particular can be designed as single stage planets or as multistage planets.
If applicable, a contact pressure system in accordance with the invention is provided with torque sensors and a transmission unit, further with a freewheel system that has one or several individual, in particular conventional, freewheels, or a double freewheel, or a freewheel system designed in some other way.
Particularly preferred are different torques that are applied to the transmission unit or the interfaces of the transmission unit to the adjoining components, whereby the largest of those torques is transmitted between the transmission unit and a torque sensor in accordance with the inventive contact pressure system.
Preferably, the torque is raised on the input side of a torque sensor, which is particularly associated with a predetermined set of disks of a transmission having an endless torque-transmitting means, or a continuously variable transmission of a motor vehicle, so that, particularly in this case, a unit is provided that has an input moment that is smaller than its output moment, so that the input moment of the torque sensor is greater than the input moment of that unit. It is not thereby intended to restrict the invention. It is further preferred that the output moment or the output force of the torque sensor is reduced so that a correspondingly diminished force will load a set of disks of a continuously variable transmission or a transmission having an endless torque-transmitting means.
The contact pressure system and/or the torque sensor, in the sense of the present invention, is configured hydraulically and/or mechanically, or in some other way.
Particularly preferred, the contact pressure system as well as the torque sensor is configured mechanically so that the force or moment transmission is brought about by mechanical parts, specifically, from the input side of the contact pressure system all the way to a set of disks.
The transmission unit of the contact pressure system can have round or non-round gears or it can be configured in some other way.
In accordance with a particularly preferred embodiment of the invention, the non-round gears are the gears of a planetary transmission.
Preferably, a portion of the contact pressure force that is produced by the contact pressure system in accordance with the invention, and which depends on the transmission ratio of a continuously variable transmission, is produced by the selection and/or configuration of the transmission unit that the contact pressure system exhibits.
Preferably, the contact pressure system generates a contact pressure force that depends both on the transmission ratio of a continuously variable transmission and on the moment with which that contact pressure system or the continuously variable transmission is loaded, where the moment-dependent portion and the gear-ratio-dependent portion of the contact pressure force are produced in different dividing mechanisms. The following is provided, in particular: the moment-dependent portion of the contact pressure force is produced via a ramp system, where those ramps in particular are designed in a linear fashion, and the portion that depends on the transmission ratio is produced via a planetary transmission with nonround gears which, in particular, is series-connected with a torque sensor with ramp system.
In a particularly preferred manner, at least one of the nonround gears has an elliptical shape. Preferably, the transmission is a planetary transmission in which the sun gear as well as the planet gears in each case are elliptical and where the ring gear is essentially star-shaped with essentially rounded transitions.
Preferably, a contact pressure system in accordance with the invention has a torque sensor with differing ramps plus a unit that determines or controls via which of those ramps a torque can be transmitted or is transmitted via the contact pressure system. This unit in particular is so designed that even in case of fast load changes, a torque transmission is possible in accordance with those load changes.
The following is provided in a preferred manner: a part of those ramps are deceleration ramps and a part of those ramps are acceleration ramps. The following is possibly provided: those deceleration ramps and acceleration ramps are at least partly uncoupled from each other, specifically in such a way that they are arranged so that they can be moved with relation to each other. By xe2x80x9cuncoupledxe2x80x9d is meant in particular that no coupling or connecting elements are provided, or that relative movement is guaranteed in spite of provided coupling or connecting elements. This relative movement can be facilitated by means of a spring system.
Preferably, a contact pressure system in accordance with the invention has a torque sensor with ramps, against which rests an additional component of the torque sensor. This additional component is guided actively or passively on that ramp so that there is essentially always a contact between that ramp and that component.
Active guidance in the sense of the present invention exists in particular when a component, especially one reacting to a load, such as a spring, brings about the guidance action, while a passive guidance exists in the sense of the present invention particularly when a working, especially a load-generating, component brings about the tracking guidance.
A preferred contact pressure system has at least one torque sensor with a first device and a second device. The first device is connected into the flow of power when a torque acts upon the torque sensor in a first direction of rotation, and the second device is connected into the flow of power when a torque acts upon the torque sensor in a second direction of rotation opposite to the first one. In particular, it is provided in accordance with the invention that a torque can be transmitted via the first or second device that is connected into the flow of power.
The first device preferably has a first ramp and the second device preferably has a second ramp. In a particularly preferred manner it is provided that the first ramp is arranged so that it can be swung with respect to the second ramp.
The first ramp is preferably connected or coupled to the second ramp via a spring element or a damper element. The ramps in accordance with the inventive contact pressure systemxe2x80x94and, in particular, the first ramp and/or the second rampxe2x80x94preferably extend in the circumferential direction of the torque sensor or at an angle with respect to that circumferential direction, or in the circumferential direction and in the radial direction. Possibly, the ramps are so designed that, with respect to the torque sensor, differing positions are provided on the surface of the ramps and different axial positions are associated with those positions.
Preferably, the first device has a first freewheel and the second device has a second freewheel. Those freewheels are uncoupled or they are coupled together. The positions of those freewheels are controlled by a common control device that controls both freewheels, or by separate control devices, or in some other way.
The first and the second freewheels are preferably coupled or connected with each other via a spring system.
During the switchover from the first freewheel to the second freewheel and conversely, a position is passed in which one can make sure that both freewheels are opened. This position is referred to especially as xe2x80x9copen centerxe2x80x9d in the sense of the invention.
The first and second freewheels are preferably known, conventional freewheels, or the freewheels are formed as a double freewheel.
The first as well as the second freewheel preferably has a clamping body. This clamping body is provided particularly to make sure that it can transmit a torque, in at least one predetermined position, between two components that are arranged so that they can be moved with relation to each other. The clamping body in particular is made as a ball, or as a roller, or the like. Preferably, a common retainer is provided for the clamping bodies of the first freewheel, as well as a common retainer for the clamping bodies of the second freewheel.
In accordance with a preferred embodiment of the invention, the clamping bodies of the first freewheel are arranged with those of the second freewheel in a common retainer.
The clamping bodies of the first freewheel and/or the clamping bodies of the second freewheel preferably cooperate with a single or with two profiled and/or nonprofiled tracks. Preferably it is provided that at least one of those profiled tracks is arranged radially outside the clamping bodies of the particular freewheel that cooperate with that profiled track.
The following is provided in particular in the sense of the invention: the first freewheel is associated with a deceleration ramp system or has a deceleration ramp system, and the second freewheel is associated with an acceleration ramp system or has an acceleration ramp system, or conversely.
Preferably, in each case, at least one clamping body of the first and of the second freewheels cooperates with a profiled track, where at least one of those profiled tracks is arranged radially inside the clamping bodies that cooperate with that track.
Preferably, there is provided at least one clamping body that is associated both with the first and the second freewheel. In particular, that clamping body cooperates both with a track of the first freewheel, that is made nonprofiled or profiled, and with a corresponding or differently designed track of the second freewheel.
Preferably, there is provided a first nonprofiled track that cooperates with at least a first clamping body of the first freewheel, as well as a second nonprofiled track that cooperates with at least a second clamping body of the second freewheel, where the first and the second nonprofiled tracks are non-rotatably connected with each other. The first and the second nonprofiled tracks are spaced apart from each other, or not spaced apart from each other, in the radial direction.
Preferably, the first freewheel has a first, profiled track and the second freewheel has a second, profiled track, and those profile tracks in each case cooperate with a first clamping body or a second clamping body, or with a common clamping body, and that the first and the second profiled tracks are spaced apart, or are not spaced apart, in the radial direction.
The first profiled track is preferably non-rotatably connected with the second profiled track, or it is arranged so that it can be moved with relation to that second profiled track.
A preferred contact pressure system has a retaining device that retains predetermined clamping bodies in contact with a second running path or track, and that is possibly spaced away from a first running path, where that first and that second running track, as well as those clamping bodies, in each case are associated with the same freewheel. Possibly, a first retaining device is provided for the first freewheel and a second retaining device is provided for the second freewheel.
Preferably, a contact pressure system has a carrier device that operates between at least one clamping body and at least one track, so that, under predetermined conditions, a movement of that track exerts a force upon the clamping body, specifically, in the circumferential direction. This force is brought about in a particularly preferred manner under predetermined conditions, when the first freewheel and/or the second freewheel is switched into an opened position. In a particularly preferred manner, the carrier device is made as a friction device or has a friction device. In particular, the carrier device has a friction ring or a friction disk that extends essentially concentrically to the freewheel or concentrically to the torque sensor.
Preferably, the clamping bodies, in case of a power transmission and/or a moment transmission, are clamped via the particular freewheel between two tracks, where the term xe2x80x9cclampsxe2x80x9d in that sense also especially means that those particular clamping bodies press against both tracks in a form-locking and/or friction-locking manner. In a particularly preferred manner, the clamping bodies are arranged between those two tracks, specifically in the radial direction.
A preferred freewheel system in accordance with the invention has differing clamping bodies that are associated with differing freewheels and that are spaced apart in the axial direction of the freewheel system or a torque sensor. Possibly, the clamping bodies are spaced apartxe2x80x94alternatively or additionallyxe2x80x94in the radial direction.
Preferably, clamping bodies of the freewheel systemxe2x80x94that are associated with the same freewheel or different freewheelsxe2x80x94are arranged in series and extend particularly in the circumferential direction of the freewheel system or a torque sensor system.
In accordance with a preferred embodiment of the invention, at least one track of the freewheel system is coupled with a component of the torque sensor and/or a set of disks, specifically with a movable component.
In a preferable manner, at least two tracksxe2x80x94that are associated with different freewheelsxe2x80x94are arranged so that they are movable with respect to each other.
Particularly, at least one track of the first freewheel is arranged fixedly with respect to a track of the second freewheel, and another track of the first freewheel is arranged so that it can be moved relative to another track of the second freewheel.
Preferably, several clamping bodies of a freewheel touch each other so that they can possibly load each other, specifically in the circumferential direction of the torque sensor.
In accordance with a preferred embodiment of a contact pressure system in accordance with the invention, the latter has a freewheel system with two freewheels or a double freewheel, where the first clamping body or the first clamping bodies of the first freewheel are arranged at a predetermined phase angle with respect to the clamping body or clamping bodies of the second freewheel and are possibly retained at that phase angle. A predetermined first running path of the first freewheel, which is associated with at least one predetermined first clamping body, is arranged with relation to a second running path of the second freewheelxe2x80x94which is associated with at least a second predetermined clamping body at a predetermined phase angle. In accordance with the invention, it is provided especially that the phase angle between those clamping bodies is smaller than the phase angle between those running paths.
A freewheel system or a freewheel in accordance with the invention is particularly designed as a double clamping roll freewheel with external stars and a common retainer, or as a double clamping roll freewheel with internal stars and a common retainer, or as a double clamping roll freewheel with common clamping bodies, or as a double clamping body freewheel with a common retainer, or as some other freewheel system, or as some other double clamping body or clamping roll freewheel system.
Preferably, the freewheel in accordance with the invention is so designed that there is a first engagement in the vicinity of a switchover point, in particular, in case of a small rotational backlash, where that switchover point in particular is a position in which both freewheels are not engaged.
Preferably, the clamping rollers or clamping bodies are constantly kept against a track by means of a spring device, or by means of centrifugal force, or by means of a form-locking arrangement, or in some other way, which are associated with those particular clamping rollers or clamping bodies.
Preferably, there is provided a friction element that, at least in the area of an xe2x80x9copen center,xe2x80x9d in other words, when both freewheels are not engaged, by way of friction connects with each other the clamping bodies or clamping rollers with a nonprofiled common running path of the two freewheels, so that a rotational connection exists due to the action of the corresponding friction force. The following is provided here in particular: in case of a relative rotation of that running path associated with both freewheels, with respect to the particular other running paths using that friction connection, the clamping rollers or clamping body rows are switched into a first engagement.
Preferably, in accordance with the invention, there are provided, with the particular freewheel, clamping rolls or clamping body rows which have one or several clamping bodies or one or several clamping rollers. Those clamping rollers or clamping body rows are preferably, in turn, connected with each other by retainers or contact each other so that the movement of one of those clamping bodies will bring about a movement of a neighboring clamping body.
In accordance with a special embodiment of the invention, the common clamping roll or clamping body row is associated with both freewheels of the freewheel system, whereby differing engagement areas are given for the different freewheels. Those different engagement areas differ especially in that a torque can be transmitted, in one of the freewheels, in differing positions of that row of clamping bodies.
Preferably, a common clamping body or clamping roller row associated with both freewheels, defined under predetermined conditions, is kept raised off a common running path, whereby that holding action is preferably brought about via a common retainer.
In accordance with a preferred embodiment of the invention, a friction element is provided which is designed as a structural unit with a possibly existing retainerxe2x80x94in the area of the xe2x80x9copen center,xe2x80x9d which connects the clamping bodies or clamping rollers in a frictional manner with a nonprofiled, common running path so that there is a rotary coupling.
Possibly, at least one running path of the freewheel system is connected with a movable part of the continuously variable transmission, in particular, with a disk or a set of disks of that continuously variable transmission. It is further preferred that at least one running path of the freewheel system be formed by a component of the continuously variable transmission, or of the torque sensor, or of a set of disks, or is arranged on it.
The following is further preferred: different running paths of the freewheel system be made up of components of the moment sensor, or be coupled to that moment sensor, or be arranged on that moment sensor.
It is further preferred that a common running path, which is associated with the different freewheels, be arranged on a movable part of the moment sensor, or be coupled with it.
The invention, of course, is not hereby restricted. In particular, the running paths, especially the running paths that are movable with respect to each other, can also be made up of other parts or may be arranged on other parts.
A running path or a track of the freewheel system is in the sense of the present invention, in particular, a surface against which a clamping body is supported whenxe2x80x94via that clamping body and that surfacexe2x80x94a force can be transmitted, or when the freewheel is in a closed position and/or the surface that adjoins the previously mentioned surface is a surface that can guide the clamping body.
By a profiled track or running path, in the sense of the present invention, is particularly mean a track that has elevations and depressions.
By an unprofiled or nonprofiled track, in the sense of the present invention, is particularly mean a track whose surface is essentially free of any elevations and depressions, or that is essentially made level.
Preferably, in an invention-based contact pressure system, or a freewheel system, or a torque sensor, there is provided, in each case, for a set of disks of a continuously variable transmission, or for several different sets of disks of a continuously variable transmission, a common contact pressure system, or a freewheel system, or a torque sensor system is provided.
A contact pressure system in accordance with the invention is particularly provided for a continuously variable transmission in order to maintain a predetermined, set transmission ratio. This continuously variable transmission preferably has, in addition, an adjusting system by means of which the transmission ratio can be adjusted. Such an adjusting system is preferably hydraulic, or mechanical, or formed in some other way. In a particularly preferred manner, the contact pressure system also operates in the case of an adjustment of the transmission ratio, and in that case, in particular, the forces of the adjusting system and of the contact pressure system are combined for the adjusting function.
Preferably, a contact pressure system in accordance with the present invention has a spring system which makes sure that the particular ramps of the torque sensor or at least one ramp of the torque sensor here, in the direction of power transmission, rests against at least one component that adjoins the particular ramp, such as power transmission bodies, and which ensures thatxe2x80x94as a function of the direction of loading of the torque sensorxe2x80x94the particular ramp, designated for that direction of loading, such as an acceleration ramp or a deceleration ramp, will be arranged in the flow of power.
To ensure that an adjoining component, such as a power transmitting body, rests against a particular ramp, it is in particular so arranged that that the power transmitting component rests against one of the surfaces between which it transmits that power or that torque when it is connected in the power flow or the torque flow.
It should be noted that, if in the sense of the invention, one talks about a ramp or a flank, is meant especially a single ramp or a pair of ramps, which are associated with each other and between which a power transmitting body is arranged, via which, between those adjoining ramps, power is transmitted via a torque, when the particular ramp is provided in the torque flow path, or an arrangement consisting of a ramp and a component with a surface that is not inclined.
Preferably, with the help of the spring system, one can determine or control which ramp, inside the torque sensor, is to be switched into the power flow or the moment flow.
Preferably, at least one ramp of the torque sensor system is coupled with a spring of the spring system. Preferably, at least one ramp of the torque sensor system is coupled via a spring of the spring system with a component that is loaded by the internal combustion engine.
In a particularly preferred manner, there is provided a spring of the spring system that is arranged between a ramp of the torque sensor and a component that is loaded by the internal combustion engine, where the flow of power from the internal combustion engine to the torque sensor system runs through that spring and, where, in particular, no other components are provided via which that flow of power can be bridged by the spring or by a spring.
Preferably, the spring system has at least one first spring that is arranged between a component loaded by the internal combustion engine and a first ramp of the torque sensor system, as well as at least one second spring that is arranged between a component loaded by the internal combustion engine and a second ramp of the torque sensor system, so that those rampsxe2x80x94especially when a motor vehicle is acceleratingxe2x80x94can be loaded by the internal combustion engine via those springs.
Preferably, a spring of the spring system is increasingly released with increasing running radius of a endless torque-transmitting means which is arranged on a set of disks of a continuously variable transmission, which set is associated with that torque sensor.
Preferably, a spring of the spring system has a prestress in the case of the maximum running radius of the endless torque-transmitting means which is associated with the set of disks that is associated with that particular spring or with the torque sensor.
The spring system preferably additionally operates as a vibration damper or as a two-mass flywheel (ZMS), or it is integrated into a two-mass flywheel which is arranged in the power train of a motor vehicle.
The contact pressure system and/or the torque sensor is in particular formed mechanically.
The power transmitting body in the sense of the present invention in particular is a roller body, such as a ball, or some other component.
The term xe2x80x9ccontrollingxe2x80x9d in the sense of the present invention in particular is to be construed as xe2x80x9cregulatingxe2x80x9d and/or xe2x80x9ccontrolling,xe2x80x9d along the lines of DIN (German Industrial Standard). The same applies to concepts that are derived from the term xe2x80x9ccontrolling.xe2x80x9d